Today's assembly procedures for stuffing PCB's often involve assembly stations that have a number of magazines with individual bins in their table tops. The electrical components required for the assembly are in the various bins of the magazines. With the help of a suitable drive mechanism, the magazines containing the bins are moved within the table top of the assembly station in such a way that precisely that bin which contains the electrical components required for a particular assembly process is delivered to the area of a pick up window within the table top.
A conventional assembly station of this type, for instance, has twelve magazines within its table top, each containing eight bins. This means that assembly procedures involving 96 different components are possible, with the pick up time being approximately 3 sec in each case. However, it has been found that in some applications of this type of assembly stations, e.g., repair procedures of already assembled PCBs or devices, or assembly procedures of complex devices such as watches, or for the compact storage of spare parts in the case of small components, a projected number of say, 100 bins with a relatively short pick up time is not sufficient.
In order to meet the requirements of this situation, delivery devices have been designed in the meantime where the movement of the magazines which contain the bins does not take place horizontally within the table top of the assembly station but in a vertical direction which would allow a larger number of bins to be used. The devices that result from this type of design are constructed in a manner similar to that of continuous conveyors since they feature the respective chain belts on both sides of the delivery device in question. It is with the help of said chain belts that the respective magazines which contain the bins can be moved along a vertical endless loop.
In the configuration of conventional conveyor devices of the type that is used to transport persons or move passenger cars to their respective places of storage, or for the accommodation of file boxes, the individual transport capsules are more or less "dangling" from the chain belts that perform the vertical transport. This, however, means that transport units of this type can be moved only at a relatively slow pace which, in turn, makes for a relatively long pick up time for the respective articles.
With respect to the achievement of short pick up times, one already known configuration of delivery devices that are based on the endless loop principle provides for additional bearing rails. By means of the latter, the magazines which run on the chain belts are effectively supported and can be placed in a horizontal position regardless of their various locations even if they move at an increased speed. However, it has been found that this type of forced guidance in the form of bearing rails requires considerable assemblage and very precise adjustment in order to keep the delivery device dependable. What is more, even if the above guidance system in form of bearing rails is installed, this will still not lead to optimum transport speed which means that the revised delivery system, with their relative bulk, will still leave things to be desired when it comes to the pick up time at the individual bins.
For the above reasons, it is an object of this invention to further develop the delivery system of the type mentioned initially so as to arrive at a configuration which will result in a relatively short pick up time at any one of the bins even in cases where there are long chain belts with a great number of bin-loaded magazines. With all this, the mechanical aspects of the configuration are to be kept relatively simple.
Based on this invention, the above will be achieved by equipping the two chain belts with pins at regular intervals, with said pins pointing toward the center, and with the holding elements which serve as support for the magazine boxes being pivoted on said pins, and by equipping said holding elements with stop members which, with reference to the chain belts, can be locked into the specified angular position.